This invention relates generally to golf clubs, and more particularly to connection of a golf club head to a shaft to achieve certain advantages.
Many efforts have been made to reallocate metallic weight from the hosel area of a golf club to the head itself, in order to achieve higher energy availability for transfer when the club is swung. Such greater energy or momentum is then transferred to the golf ball when struck. This requires, for example, reduction of metal at the hosel area of the club.
Such efforts have included configurations wherein a shaft passed through the head of a persimmon wood. Typical of such configurations were: Wilson's staff model "Dynopower Fluid Feel" wood, produced around 1957; Wilson's "Helen Hicks" wood, produced in the 1920's; and certain MacGregor woods, produced in the late 1930's. See also U.S. Pat. No. 4,995,609 entitled "Iron Golf Club Heads" assigned to Callaway Golf Company, disclosing a hosel characterized by reduced mass or weight.
No way was known, to our knowledge, to connect a shaft to a golf club iron head, where the shaft passed into proximity to the bottom of the head and was reduced in diameter at or near the bottom of the head so as not to interfere with an edge or edges of the sole; also, no way was known to connect such a shaft to a non-constant tapered bore in an iron hosel to provide a tight interference fit along localized extent of the shaft and bore, upon axial assembly, enabling very good tactile "feedback" sensing, to the player, of head-to-ball impact, and also providing annular space for adhesive reception between the shaft and bore near the bore taper.
Further, locking of the collapsed end of a shaft to a bore, by local expansion of the collapsed end, was not known.